July 8, 2013
How to create a DIY Matrix bullet time/time slice rig using a ceiling fan and a GoPro
For July 4th I created the following video of fireworks.
I’ve always been fascinated by the time slice technique (also known as “bullet time”). Probably the most famous version of this comes from a scene in the first Matrix film where Neo dodges a series of bullets. To capture this look the filmmakers set up an array of cameras that fired off at high speeds in sequence. After a lot of work interpolating frames (creating frames between frames) using an in-house software program (now known as Twixtor), they were able to achieve the final effect.
I’ve always wanted to try this, but you need an array of cameras, and cameras are expensive.
The obvious “cheat” to this is to get a high speed camera and build a rig that will spin it around the subject, but this also has limitations. High speed cameras are still expensive, they weigh a lot, and building spinning rigs out of metal is also expensive. A friend sent me a video by Mark Rober who came up with the idea of using a ceiling fan as the spinning rig, and a GoPro 3 for the high speed camera (which shoots up to 240fps). I decided to implement this idea, but instead of mounting the fan upside-down, mount it the correct way so I could film larger subject matters.
Here is a video showing how I did it.
The ceiling fan was purchased from Lowes, it was one of two left on sale for $24.00. The fan is attached to a 14 foot 2×4 (if I did it again I’d use a 2×6).
Wiring was pretty simple. Two were for the fan, one was for the grounding, and a fourth was for the light, so I didn’t hook that one up.
The orange cord came from the fan and connected with the blue control box. The black cord came from the blue control box and hooked into the power source.
I used a section of 1 inch pine wood to attach my GoPro to the fan blade (via a hinge).
My GoPro was attached to the pine wood with a 3M GoPro stick mount. They are VERY sticky, but I super glued it on just to be safe.
8 foot 16 gauge extension cord: $10.47
Assorted wingnuts: $2.91
Deck screws: $9.37
14 foot 2×4: $6.58
Lag screw (attached fan to the board): $0.24
Utility hinge: $1.67
Utility bolts: $0.97
1 inch x 3/8 inch pine wood: $5.52
Ceiling fan: $24.99
Speed regulator and recessed wall box: Under $15 for both, I lost the receipt for these items